With regard to durability, I think the predator EU is all over the place. It really depends on whether you want to go by high showings or low showings.

In this one comic (Predator: Hell Come a Walkin'), the predator survives an artillery shot to his immediate vicinity. The human standing next to him is ripped to pieces, the blast doesn't even break the predator's skin. Yet the same predator falls to the ground helpless when a human stabs him in the back with a flagpole.

I suppose you could argue that the predator was more hurt by the blast than he appeared to be or that the human got lucky and skewered the predator through a really vital organ...but I think what's really going on is that the pred is squishy when the writer needs him to be squishy and super tough when the writer needs him to be super tough

Even so...being rendered helpless by mere impalement with a flagpole is inconsistent with the predator's durability in other sources. For example:

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Coming from a different angle, the bullet entered the Predator's body. This third bullet lodged deep inside, coming to rest only after it had cut through several vital organs.. . . "The demon isn't dead yet," said Sukhon."The 'demon' will be dead if it doesn't get some expert medical attention. I put a bullet with an exploding tip right through its back. No exit wound.". . . Still, the Predator's condition did not yet warrant self-destruct. He had been hurt worse and emerged victorious. Once on a planet half a galaxy away, a venomous metal worm twice his size had shot up through the earth and pinned him through the chest armour. The Predator had chopped its head off, cut off its tail, and gone on to fight for another four hours with the rest of the worm inside his chest, before withdrawing to repair the damage. The wheeze as its breathing grew worse indicated deep-tissue damage, but nothing irreversible. Medical care on board its ship would allow it to recover.